According to our law enforcement sources, 28-year-old Lewis was found in a driveway Wednesday morning in the Los Feliz neighborhood -- and the elderly woman who owned the home was found dead inside ... the victim of a homicide. Investigators say they believe Lewis beat the woman to death.

According to multiple reports, neighbors heard the 81-year-old woman screaming ... and then saw a young man outside her home attack 2 other people with a piece of wood ... before he climbed onto the roof and fell to his death.